Yes. There are a lot of hypenated-words and compound words in the English language that are formed from a verb-adverb combinations like this. Some examples: get-up, makeup, drive-up, drive-by, drive-through, run-up, make-over, fly-over, walk-up, stand-up. Many are nouns.

I am British and we do use it in that way though we spell "organize" with an 's' not a 'z' so in the UK we would say "I'm organising a get-together." Hope this helps!

Actually, I'd guess get-together is a word more commonly heard from the older generation. Maybe younger ones will have other words.

Thank you. Is "attend a get-together" a common practice ?

I'd guess there is no verb "get-together". Maybe we should get together & discuss it?